ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5aNS6. Application of computational fluid dynamics (CFD) to automobile wind noise source minimization.

Keng D. Hseuh

Sanjay Abhyankar

Sanjeeva Addala

Anant Kamat

Chun Wu

Mike P. Haffey

Vehicle Wind Noise & Road NVH Dept., Core & Adv. Veh. System Eng., MD 45-Adv. Eng. Ctr., Ford Motor Co., 20000 Rotunda Dr., Dearborn, MI 48121-2053

Wind noise is becoming a critical comfort requirement to customers due to greatly reduced powertrain and road noise, particularly at high-speed driving conditions. The physical phenomenon generally can be categorized into: sources (A-pillar vortex and mirror wake) and path (door/window weatherstrip leakage). Two different vehicle greenhouse geometries that produce attached- and vortex-flow, respectively, were used in this A-pillar vortex minimization case study to correlate the CFD predicted A-pillar vortex size and sideglass pressure distribution (Cp) with measurements from wind tunnel testing. A-pillar vortex and pressure distribution have been shown to be key factors affecting wind noise excitation on sideglass and shape-induced aerodynamic suction force on door/window (which is required in designing door/weatherstrip to prevent aspiration leaks through weatherstrip under high-speed condition), respectively. Results demonstrate that the CFD can successfully predict the effects of geometry changes on A-pillar vortex size and Cp within >80% accuracy under various speeds/yaw angles. This study confirms that CFD can be applied with confidence as an upfront engineering tool to optimize vehicle greenhouse geometry for minimum wind noise excitation in a cost and time effective manner.